Seats such as vehicle seats and indoor sofas are made up of a seat pad that is composed of, for example, a polyurethane foam and a skin material that is attached on a surface of the seat pad. A skin material is fixed onto a surface of a seat pad by a method in which a fastener such as a hook-and-loop fastener is provided on a surface of a seat pad and the skin material is fixed onto the surface of the seat pad through this fastener. Such a fastener is arranged along an inner surface of a seat pad molding mold and a foamable resin material such as urethane is foamed within the mold so as to form a seat pad integral with the fastener.
An example of such a fastener is a synthetic resin hook-and-loop fastener which has a strip-shaped base portion extending along a surface of a seat pad and is provided with an engaging portion on one surface of the base portion that can engage with an engaged portion of a skin material and an anchor portion on the other surface that is buried within the seat pad. Patent Literature 1 listed below describes that a rail that is recessed in cross section is provided along an inner surface of a mold and a hook-and-loop fastener is engaged with the rail and is thereby retained on the inner surface of the mold.
FIG. 3 is a schematic vertical sectional view that illustrates such a synthetic resin fastener 7 arranged along an inner surface of a mold 8. Because the synthetic resin fastener 7 has a relatively high flexural rigidity, it is not easy for the fastener 7 to be deformed so as to follow the contour of the inner surface of the mold when the inner surface of the mold 8 is curved. As a result, there is a risk that the fastener 7 will be partially lifted from the inner surface of the mold as illustrated in FIG. 3.
In order to solve such a problem, Patent Literature 1 describes that a plurality of fasteners that have been cut into short lengths in accordance with the curvature radius of the curved surface of the mold are arranged along the curved surface.
Patent Literature 2 listed below describes that a fastener contains a magnetic material and magnets are buried within an inner surface of a mold so as to attract the fastener and cause it to become curved along the curved surface of the mold and to be fixed thereto.
In the production of a foam molded resin article using a mold consisting of an upper mold section and a lower mold section, a foamable resin material such as urethane is supplied into the lower mold section, the mold is clamped, the resin material is foamed and hardened (cured), and the mold is opened to allow the article to be released therefrom.
FIG. 4 is a flow diagram that illustrates a process of producing a foam molded resin article which is integral with a secondary material such as a fastener. This production of a foam molded resin article has a cycle in which a release agent is applied to an inner surface of a cavity of a mold (a release agent application step 1), a secondary material is set within the cavity (a secondary material assembling step 2), a foamable resin material is supplied into the cavity, the mold is clamped and the foamable resin material is heated and foamed (a foam molding step 3), the foamed resin material is cured (a curing step 4), and thereafter the mold is opened and the molded article is released therefrom (a mold release step 5). After the molded article is released from the mold, the process returns to the release agent application step 1 and the next cycle of foam molding starts.
Patent Literatures 3 and 4 listed below describe methods for continuously producing such foam molded resin articles in which the molding molds are sequentially transferred to the step 1 through the step 5 by wagons or a turntable.